1. Field of the Invention
This invention relates generally to collapsible pallet racks and more particularly to a collapsible and stackable steel rack for shipping and storing heavy roll goods.
2. Description of the Related Art
Collapsible steel pallet racks were first developed in the late 1950s by the Clark Equipment Co. of Battle Creek, Mich., to replace wooden pallets for storing and transporting heavy awkward articles, such as automobile engines. An exemplary prior art steel pallet is shown in U.S. Pat. No. 2,956,763 which issued on Oct. 18, 1960, to Nicholas D'Arca.
During the 1960s, the textile industry developed various heavy duty, strong racks for yarn-carrying beams. Examples are given in U.S. Pat. No. 3,084,803 which issued to Bayers on Apr. 9, 1963; in U.S. Pat. No. 3,355,029 which issued to Eurey on Nov. 28, 1967; and in U.S. Pat. No. 3,430,773 which issued to Hancock on Mar. 4, 1969.
During the 1970s, improved foldable shipping racks for heavy items, such as automobile engines, were developed in both the United States and Japan. Such racks are shown in U.S. Pat. No. 3,804,033 which issued to Izawa et al. on Apr. 16, 1974, and in U.S. Pat. No. 4,098,409 which issued to Massey on Jul. 4, 1978. These developments were satisfactory to carry industry through the 1980s.
However, during the 1990s, a need developed for more durable, reusable, foldable, transporting and packaging racks for mechanically sensitive goods in the form of large rolls. This need was met by various racks manufactured in both the United States and Germany. Such racks are illustrated by U.S. Pat. No. 5,228,821 which issued to Gleffe et al. on Jul. 20, 1993; U.S. Pat. No. 5,242,255 which also issued to Gleffe et al. on Sep. 7, 1993; U.S. Pat. No. 5,692,625 which issued to Filipescu et al. on Dec. 2, 1997; and U.S. Pat. No. 5,941,398 which issued to Harris on Aug. 24, 1999.